Comparison between a two- and a three-dimensional arc plasmaconfiguration

Abstract

A three-dimensional (3D) argon arc plasma at atmospheric pressure ispresented. The model is developed using the commercial code Fluent. Two arcplasma configurations are studied: a free burning arc and a transferred arc.In the free burning arc configuration, the 3D results are compared with atwo-dimensional (2D) configuration. The natural axis of symmetry of thesystem, given by the physical operating conditions and by the cathode tipgeometry, leads to a good agreement between the 2D and 3D results. The modelis validated by comparisons with experimental and theoretical temperaturefields. The results show a small difference between the 2D and 3D models, asdoes the other literature. In the transferred arc configuration model theinjection is given by three injectors. A rigorous modelling of the injectioncannot be treated using a symmetric plane or a symmetric axis, so the resultsare presented in a real 3D configuration and compared with results obtained ina 2D configuration. Indeed, in a 2D configuration, due to the symmetricalcondition on the axis, the main assumption consists of representation of thereal injection geometry by an equivalent surface injection. The imposed massflow rate is then distributed along a ring and differences can appear in theresults.